EPOCHS IN BIOLOGICAL HISTORY 385 



path to progress was blazed by men whose plans were less 

 ambitious. Contemporaries of Gesner, who confined their 

 treatises to special groups of organisms which they themselves 

 investigated, really instituted the biological monograph which 

 has proved to be the effective method of scientific publica- 

 tion. 



While the herbalists, encyclopaedists, and monographers 

 at work in natural history were making brave endeavors to 

 develop the powers of independent judgment, which were 

 oppressed to such an extent during the Middle Ages that the 

 very activity of the senses seemed stunted, the emancipator 

 of biology from the traditions of the ancients appeared in the 

 Belgian anatomist, ANDREAS VESALIUS (1514-1564). Dis- 

 gusted with the anatomy of the time, which consisted almost 

 solely in interpreting the works of Galen by reference to crude 

 dissections made by barbers' assistants, Vesalius attempted 

 to place human anatomy on the firm basis of exact observa- 

 tion. The publication of his great work On the Structure of 

 the Human Body made the year 1543 the dividing line be- 

 tween ancient and modern anatomy, and thenceforth ana- 

 tomical as well as biological investigation in general broke 

 away from the yoke of authority and men began to trust 

 their own eyes. 



The work of Vesalius was on anatomy, and physiology was 

 treated somewhat incidentally. The. complementary work on 

 the functional side came in 1628 with the publication of the 

 epoch-making monograph on the Motion of the Heart and 

 Blood in Animals by WILLIAM HARVEY (1578-1657) of Lon- 

 don. No rational conception of the economy of the animal 

 organism was possible under the influence of Galenic physi- 

 ology, and it remained for Harvey to demonstrate by a 

 series of experiments, logically planned and ingeniously 

 executed, that the blood flows in a circle from heart back to 



